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TAE MaRINE. REVIEW ~ 35 I may further say that it is a machine in which a very small number of parts can be used, as compared with the number of parts used or proposed with other types of turbines. These matters are all of very great importance, because they make possible the use of very cheap, simple and light constructions with the Curtis turbine. In our electrical work, which is high speed work, our construc- tions are necessarily very strong and there is great strain to be dealt with. In the marine problems these strains will not exist, and consequently a very much less expen- sive type of construction can be made practicable. There is another thing which may be said about the Curtis tur- _ bine, and in fact, about turbines generally, that while the calculation of the performance of a turbine is a compli- cated and intricate problem and one of which we can never be absolutely certain as to theoretical solution, the nature of the turbine is such, or the nature of the Curtis turbine is such, that the experimental results obtained on a small scale are an absolute criterion as to results which can be accomplished on a large scale; and this is evidenced by the experience which I will mention of the construction of 5,000 kilowatt turbines in large numbers on commer- cial orders on the strength of the results obtained with a two-inch diameter experiment delivering 150 horse power. In the Parsons type of turbine the thrust must be ba- lanced, and the balancing of this thrust must involve cer- tain loss through clearances. The amount of clearance required--the amount of clearance used, will govern the economy in a sense, and the losses will vary if the adjust- ment varies. With the Curtis turbine no such limitation exists, because thrust is absent, except such thrust as comes from the propeller. The Curtis turbine--its econo- my is independent of the clearance, in'fact of the actual clearance of the buckets within such limits as we need to consider; and for this reason a test of certain buckets on a small wheel is an absolute guarantee of the performance of the same buckets or similar angle buckets on.a large wheel. To illustrate the simplicity of construction of. the Curtis turbine design for slow speed, I want to make a very rough sketch. (Here Mr. Emmet illustrated on the blackboard.) You have got a construction there which can be made strong and stiff with a very light weight, and its course will probably develop to be more comparable with the cost of decks and hulls than it will with the engines. This drawing would apply to a Curtis turbine of the marine type, in which a number of buckets can be used "in a single shaft. Admiral Bowles has mentioned the possibility of pilot house control. I want to say that the turbine built by the General Electric Company now is controlled week in and week out from the pilot house practically, but the pilot house does not have any pilot in it. It is a distinct control from a controller operated by the speed governor, and these machines--many hundreds of them are in use and have been in use for months, and some for years, without care or attention, and they will continue so for many, many years more before any work or expense will be occasioned in connection with them. The question has been raised as to the trouble experienced with turbines. We have had in our work many troubles, many serious troubles through various kinds of miscalcu- lations and misunderstandings. Our first wheels were steel discs, and some of them under certain conditions of casting strains would buckle. When we began we did not know what our clearances should be without effecting steam economy, and we had trouble with the wheels touch- ing. We have since found ways of preventing the buck- ling of the wheels, and we have found that we can increase our clearayces on large machines without affecting the steam economy. We also had trouble with our governing mechanism. Our valves stuck. All those 'troubles, how- ever, have been overcome, and about the last turbines that _ we have are two operating in Boston, five thousand kilo- watt, which have been operating there for a year, and there has never been a minute's trouble with them of a mechanical character. They are doing considerably bet- ter than the steam guarantees made upon them. But they are not as good as we can build now with our later expe- rience, because these machines were built before we had experience with the large machines. Our present work-- we are building very large turbines--we are building now six 8,000 kilowatt capacity, with. a maximum output of 12,000 kilowatts, something like 17,000 H. P.--we are _ building six of those, and we expect to get from those-- in fact, we are certain of very much better steam eco- nomies than are produced on any large engine. To pro- perly apply the turbine is a great problem, and is a prob- lem which will require engineering skill and daring, and if anybody thinks that he can get the product ready made and apply it to a ship without that--without having p-ac- tical difficulties, why he would probably deceive- himself (Applause). Mr. D. W. Dickie: Mr. Chairman, there are one or two questions which I should like to ask Mr. Curtis. There was one brought out by the previous speaker. He men- tioned that all these parts of this roto were balanced be- fore they weve put together, and that that was one of the difficulties that was very strong in the roto of the Parsons turbine. I saw one of those turbines being fitted up. And it was taken apart quite' a number of times and filed and chipped in order to get the roto properly balanced so that the center of gravity was on the axis of rotation. I have forgotten the technical name, but in the Curtis turbine have you had any difficulty with the rocking moments set up by the pitch of the vessel on any boat that has been tried; that is, where the roto of the turbine.in revolving pitches, there is a motion forward and a rotary motion producing a condition which turns the turbine on its base. This was very carefully figured out by Prof. Garv on the Parsons turbine on the *ew large Cunarders, and it was found that the points of support on the Parsons turbine are so far. apart that the actual strain was unin- telligible, except: where the structure would have to be made strong enough to take up this strain. I think if James Watt had lived in our time or Mr. Bowles had lived in Watt's time, they would have been very fast friends, as Watt is quoted as having said that the turbine engine was the engine of the future. Then with regard to Mr. Parsons, I think he is very much like the miller and his son in Esop's fables--he is not making mistakes by taking everybody's advice. Then there is one other point that I would like to know something about, and that is the friction on the moving parts, comparing small turbines with large ones, do they follow the law of con- troversion. of energy as the friction--the resistance of driving a shaft through the water does. Mr. James G. Winship: I would like to ask Mr. Curtis if the turbine engine can be made of suitable size to drive auxiliaries. A large engine uses no lubri¢ation and no oil. Now, if we could use the turbine for the auxiliaries, it would be a very good thing. If we can get the turbine to run at the right speed with small power, I think all the auxiliaries could be operated by a turbine engine. In other words, within a thousand revolutions--from 800 or 1,000 revolutions then, the auxiliaries could be operated very nicely with turbine engines. I would like Mr. Curtis to answer that question. ' The Chairman: I think that has already been answered. Mr. C. H. Crane: I have heard a great deal about the